Operation Superior:

Multimedia Geochemical and Mineralogical Surveys

Introduction

In 1996, the Manitoba Geological Survey initiated a five-year helicopter and fixed-wing multimedia geochemical and mineralogical survey of Archean greenstone belts in a 126 000 square km area of the northern Superior Province in east-central Manitoba. Areas surveyed in each year are presented in Figure 1:

Figure 1: Target areas for multimedia geochemical and mineralogical surveys, 1996-2001. (PDF, 170 kb)

The mandate of this program was to develop an exploration-supportive database that would assist and stimulate mineral exploration in the region. The approach was to collect rock chips, till, b-horizon soil, humus and vegetation samples on a 1 km square grid within the known mapped limits of the greenstone belts. These samples were analyzed using state-of-the-art and innovative analytical technologies. Bulk till samples (25 kg) were also collected for kimberlite indicator mineral chemistry.

The five-year project was completed in 2000. An additional survey was undertaken in 2001 in response to a significant diamond exploration play that developed in east-central Manitoba.

The Database

Data have been released annually in open file reports. Reports comprising hardcopy and digital information are available for all surveys with the exception of the results for 1996, which are available in hardcopy only. Multimedia geochemical results from 2000 will be released in spring 2002.

Refer to the Bibliography of the northern Superior Province (1996-2001) for a listing of these reports and other recent publications on the northern Superior Province. Open Files and other resports and maps published by trhe Manitoba Geological Survey are available for purchase through Publication Sales.

Geochemical and mineralogical data are presented in Excel data sheets for each sample type complete with UTM coordinates. The data are summarized in the reports as percentile bubble plots based upon non-transformed data.

A compilation of all data from the five years of kimberlite indicator mineral surveys has also been released. The following figures 2 through 8 represent the areal distribution of indicator minerals in the Operation Superior survey area.

Figure 2: Cr-spinel abundances in the Operation Superior survey area. (PDF, 551 kb)

Figure 3: Cr-diopside abundances in the Operation Superior survey area. (PDF, 546 kb)

Figure 4: Ti-Cr pyrope abundances in the Operation Superior survey area. (PDF, 547 kb)

Figure 5: G9 garnet abundances in the Operation Superior survey area. (PDF, 546 kb)

Figure 6: G10 garnet abundances in the Operation Superior survey area. (PDF, 546 kb)

Figure 7: Mg-ilmenite abundances in the Operation Superior survey area. (PDF, 547 kb)

Figure 8: Total kimberlite indicator mineral abundances in the Operation Superior survey area. (PDF, 548 kb)

Western Superior NATMAP

The Western Superior NATMAP project aims to provide a modern geoscientific synthesis of eastern Manitoba and northwestern Ontario through the collaboration of the federal, Manitoba and Ontario geological surveys. Key areas were selected for mapping at a variety of detailed and regional map scales to address questions regarding relationships between Mesoarchean (>2.8 Ga) and Neoarchean (2.8–2.5 Ga) sequences of the western Superior Province. The objective was to develop a better understanding of the tectonic evolution and mineral potential of the western Superior Province. The project focussed on well-exposed parts of three structural subprovinces (central Wabigoon, western Uchi, and Sachigo) because they are known to contain both Mesoarchean (pre-2.8 Ga) and Neoarchean (ca. 2.7 Ga) supracrustal sequences as well as significant mineral deposits (volcanogenic massive sulphides and gold). New and existing mapping, geochemistry and geochronology were integrated to establish the distribution and contact relationships between Mesoarchean continental and younger Neoarchean oceanic/arc crustal fragments. The results clearly demonstrated the importance of these boundaries as the locus of major mineralizing events.

The following bedrock mapping programs, undertaken during Operation Superior, provide a better base for understanding the potential for gold, nickel, platinum group metals, rare element pegmatites, titanium/vanadium oxides, and diamonds in the northern Superior Province.

• 1:50 000 scale mapping of the Stull-Kistigan, Edmund and central Gods lakes area
   
• value-added remapping of greenstone belts in key sectors of the Oxford Lake – Gods Lake – Knee Lake region, during which new geochemical and isotopic data were acquired
   
• upgrading the 1:250 000 scale Oxford House sheet (NTS 53L) and production of a new 1:250 000 scale map of the Stull Lake sheet (NTS 53K)
   
• mapping of gabbro and anorthositic complexes in the Pipestone Lake, Kiski Lake, Hairy Lake, Butterfly Lake and Gunisao Lake regions to determine their potential for additional occurrences of titanium/vanadium-rich oxides
   
• thematic mapping and structural studies in the Island Lake, Cross Lake and Red Cross Lake areas
   
• new 1:20 000 scale mapping of the Ralph Lake – Anderson Lake greenstone belt to provide geological context for areas of prominent hydrothermal alteration and associated base metal and gold anomalies identified during the second year of the multimedia geochemical program
   
• U-Pb and Nd-Sm geochronological studies and thematic mapping in the Assean Lake area has documented 3.2 Ga and older crust at the northwest margin of the Superior Province

Preliminary maps and reports published for the mapping programs are listed in the Bibliography of the northern Superior Province (1996-2001). Two 1:250 000 bedrock geology maps, postered at the Manitoba Mining and Minerals Convention in Winnipeg in November 2001, are slated for release in 2002. A 1:2 000 000 scale compilation (see figure 9 (PDF, 3.7 M) for a diagramatic representation) of the region from east of Lake Nipigon in Ontario to the western margin of the Superior Province is planned for spring 2003.

Minerals and Geological Database Systems

A large number of digital data sets are currently available for the northern Superior Province in Manitoba, including scanned mineral assessment reports, new geological mapping, whole-rock geochemistry, isotopic studies, geochronology, multimedia geochemical surveys, and mineral deposit databases. Data collection, sorting, processing, analysis and display techniques have been developed through the acquisition of Unix and PC-based ARCINFO Geographic Information Systems. These systems will permit integration of federal datasets and generation of synoptic, electronic databases as well as coloured hard copy outputs.